What about the columns?
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| Silver Spring Transit Center, "Structural Evaluation of Superstructure", March 15, 2013, Vol. 2, pg. 293 |
How will repairs to "certain beams and girders" and a concrete overlay "fix" cracking in the SSTC's columns?
Answer: they won't.
One of the significant findings of KCE's report is that the SSTC doesn't have any expansion/contraction joints. Standard design and construction practice and WMATA design and construction standards require expansion/contraction joints in structures exposed to temperature changes. WMATA design and construction standards, to which the SSTC was supposed to have been designed and constructed, require expansion/contraction joints be spaced no more than 100 feet apart. The 315 ft. by 580 ft. SSTC has none.
Not long after KCE's report was released, Bryant Foulger of Foulger Pratt, the SSTC's builder/contractor, said that "the SSTC is like a tightly wound snare drum".
When the SSTC tries to expand or contract because of changes in temperature, hot or cold respectively, it can't, because it has no expansion/contraction joints. The monolithic, post-tensioned, concrete SSTC is like a tightly wound snare drum, and it cracks. Without expansion/contraction joints, the SSTC will continue to crack even after it's "fixed" with its "repairs required to increase the combined shear and torsional capacity of certain beams and girders" and its concrete overlay.
Nice analogy, Mr. Foulger! The only problem is that you can loosen a tightly wound snare drum; but, you can't loosen a 315 ft. by 580 ft. monolithic, post-tensioned, concrete structure that doesn't have any expansion/contraction joints. Without expansion/contraction joints, the SSTC will continue to crack, even after it's "repaired".
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| Silver Spring Transit Center |
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